Skidmore, Thomas E.
Oxford University Press, 1984
Buku Teks
Rippy, J. Fred
University of Michigan Press, 1958
Buku Teks
Meade, Teresa A.
Wiley-Blackwell, 2010
Buku Teks
edited by Eduardo P. Archetti
MacMillan Education, 1987
Buku Teks
Szulc, Tad
Atheneum, 1966
Buku Teks